Rename runAsync to scheduleMicrotask.

tests/html/events_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library tests.html.events_test;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
@@ skipping 79 matching lines @@
     // rely on this. We therefore wrap it into an expectAsync0.
     runZoned(expectAsync0(() {
       Zone zone = Zone.current;
       expect(zone, isNot(equals(Zone.ROOT)));
 
       var sub;
 
       void handler(Event e) {
         expect(Zone.current, equals(zone));
 
-        runAsync(expectAsync0(() {
+        scheduleMicrotask(expectAsync0(() {
           expect(Zone.current, equals(zone));
           sub.cancel();
         }));
       }
 
       sub = element.on['test'].listen(expectAsync1(handler));
     }));
     element.dispatchEvent(new Event('test'));
   });
 }